I agree mostly with illuminatri as usual. The most important thing he mentioned is to tighten that feeder.
Also don't use the canned settings. Look at advanced and expert settings. Know what they all do eventually.
I disagree about the higher temp. For something like the busts, yes go with higher temp. For something like that test piece with all the things sticking up you might want to go lower temp - see this:
If you plan to always print small things because you like small things better then you should also consider going thinner layer height (.1mm instead of .2mm).
The bottom layer is hard to get really good because leveling is so critical. The top layer if flat can be improved by making it thicker (2X or 3X layer height). Always make walls an integer multiple of the nozzle (so .4 or .8) and always make floor/ceiling integral multiple of layer height.
Not sure what you mean about pathway not optimized but I suspect you might want to try kisslicer or the new cura which is coming out soon (in beta now). You might be talking about what we call the "z seam".
"slicer seems to ignore small featuers even if they are big enough for a .4 nozzle" I assume you are talking about what we call "thin walls". If you have a 1mm thick wall in the stl and cura walls are set to .4 then it will leave a .2mm gap. This is a problem fixed in both kisslicer and the "new" cura (in beta). There are current hack methods to fix this - you could lie and say your nozzle is .3mm. But better to wait for the new cura.
I think there are a lot of different issues here that are going to take a little while to isolate and work through. But here are some thoughts to consider:
1) You seem to be printing a lot of very small things. That is technically quite challenging, because you need to make sure that lower layers have enough time to cool and solidify before you pile more heat on top. Otherwise, the lower layers will tend to droop and deform. The minimum layer time in Cura helps with this - I generally use a minimum layer time of 7 seconds for PLA which I print at about 220º normally. However, with very small things, slowing down can be counter productive because the head slows down so much that it transfers excess heat into the model anyway, just by lingering over each part. So be sure and set a minimum layer time, but also try printing some slightly bigger parts while you are calibrating things.
2) Circles can end up not round because of backlash in one or other axis, or due to poor layer adhesion resulting in the plastic getting pulled straight. Again, printing some larger parts to begin with will help avoid some of the noise of short, fast moves, head ooze etc, and give a clearer picture of what is really going on. Small prints tend to magnify the impact of small errors, and whats going on can get lost in the random variation of the print. Start by tweaking the printer to print large things well at a 0.2mm layer height, and then once you have that set up well, you can refine things to get equally good results with smaller prints and smaller layers.
3) I don't see any mention of what temperature you are printing at. I'd recommend try a fairly hot temperature - say 230º, and printing at 50mm/s, with 0.2mm layer height, and 0.8mm wall width to begin with. Trying to print too fast can definitely lead to extrusion problems, if you end up extruding too fast for the nozzle. The limit depends on the temperature of the plastic. Printing with those settings should put you in a fairly comfortable middle ground where you can rule out excess speed and insufficiently fluid plastic.
4) Regarding bed levelling. I'm not exactly sure how you are using 'a caliper' to level the bed. Your levelling print looks like the bed isn't level in all the corners, and is too far from the head in most, if not all, of them. The simplest thing to do is to just heat up the nozzle, autohome the z axis, and then manually move the head near to each of the 4 bed screws. Slip a sheet of paper between the nozzle and the bed, and adjust the screw tighter, until the paper can be slid easily back and forth without catching on the head. Then loosen the screw, until the nozzle just begins to catch on the paper. Then loosen the screw another 1/8 turn. Repeat in each corner. Make sure that the underside of each screw head ends up in contact with the bed when you're done. And also make sure that the washers on the springs aren't caught in the keyhole slots (I found it made a huge difference to add bigger washers under the bed).
5) It's possible (but not massively likely) that the bed really is bowed. But I'd follow the process in step 4 first. Then once all four are set, move the head to the middle, and see if you can just slip the paper back under the nozzle with the barest of downward presses on the bed.
6) You seem to be underextruding pretty much everywhere. This is what causes solid surfaces to not fill in properly. This can happen for a number of reasons, including:
a) Using a filament diameter that is less than the diameter stated in the slicer config
b) Printing too fast/thick for the temperature
c) Having your filament feed mechanism be improperly set up. You should have clear deep impressions in the filament as it passes into the bowden tube, but the plastic shouldn't be chewed up or deformed. You might want to try adjusting the tension on the feeder spring. The spring shouldn't be compressed all the way, nor should it be too loose.
d) incorrect steps-per-e setting
7) Slicers are far from perfect. Try different ones, and see what works best for different types of print.
8) Don't bother with the quickprint settings in Cura - go into the full user interface mode, so that you get a proper sense of all the settings that are available, and can begin to tweak things to improve things. The standard modes aren't bad for real-world prints, but are a bit crude for trying to evaluate difficult test prints.
9) Print real world things that you actually like and want - only worry about calibration and test pieces to the extent that they help you print real stuff better. Those test pieces are basically designed to fail at some point; don't worry too much that they do. The only problems that you need to solve are the ones that show up in real prints. :-)
10) Be sure and configure and use retraction. For PLA you will want a distance of 4.5mm, and a speed of around 30mm/s if you have built your own firmware recently, or 40mm/s if you are using the stock firmware from any of the recent Curas. (There is a bug in older firmwares which means that retraction speeds are broken. With fixed firmware you need a speed around 25-35. With the older ones you need a speed of about 40 (which is really 20)). IIRC, the standard profiles in Cura don't use retraction at all, and you seem to be getting a lot of stringing.
11) The reality is that plastic does shrink as it cools, so dimensions are going to be slightly off, and some warping may well occur. With any large, flat, solid pieces that are especially prone to curling, you can minimize the effect of that by wiping down the blue tape with isopropyl alcohol before you start printing. That will stick the base very solidly to the tape, and the tape to the bed. That can't totally avoid warping higher in the print, but it should keep the base firmly stuck.
So, some recommendations....
- Re-level the bed as described above
- Change to the full settings in Cura, and print at the mid-range settings I mentioned... get things sorted out at those settings before pushing the envelope by going faster/thinner.
- Check your filament diameter, and extruder tension to try to fix the under-extrusion issues.
- Focus on printing larger objects that you want to print for their own sake. Ultimately the art of 3D printing lies in figuring out how to adjust the settings to best print any given object. To do that, you need to build up experience printing stuff. Calibration prints can drive you nuts. :-)
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